"it's not terribly different from a random attack in the street or a shopping mall" You are right. However, the one difference is the reaction to an attack. It

"it's not terribly different from a random attack in the street or a shopping mall" You are right. However, the one difference is the reaction to an attack. It is fairly straightforward (these days) to get responders on the scene in a mall. A shooting or knife fight in an airplane is much harder to contain or react to. Overall though, I agree with Schneier about the need for intelligence replacing TSA check points.